C Specification

Function pointers for all Vulkan commands can be obtained with the command:

PFN_vkVoidFunction vkGetInstanceProcAddr(
    VkInstance                                  instance,
    const char*                                 pName);

Parameters

  • instance is the instance that the function pointer will be compatible with, or NULL for commands not dependent on any instance.

  • pName is the name of the command to obtain.

Description

vkGetInstanceProcAddr itself is obtained in a platform- and loader- specific manner. Typically, the loader library will export this command as a function symbol, so applications can link against the loader library, or load it dynamically and look up the symbol using platform-specific APIs.

The table below defines the various use cases for vkGetInstanceProcAddr and expected return value (“fp” is “function pointer”) for each case.

The returned function pointer is of type PFN_vkVoidFunction, and must be cast to the type of the command being queried.

Table 1. vkGetInstanceProcAddr behavior
instance pName return value

*1

NULL

undefined

invalid non-NULL instance

*1

undefined

NULL

vkEnumerateInstanceVersion

fp

NULL

vkEnumerateInstanceExtensionProperties

fp

NULL

vkEnumerateInstanceLayerProperties

fp

NULL

vkCreateInstance

fp

instance

core Vulkan command

fp2

instance

enabled instance extension commands for instance

fp2

instance

available device extension3 commands for instance

fp2

any other case, not covered above

NULL

1

"*" means any representable value for the parameter (including valid values, invalid values, and NULL).

2

The returned function pointer must only be called with a dispatchable object (the first parameter) that is instance or a child of instance, e.g. VkInstance, VkPhysicalDevice, VkDevice, VkQueue, or VkCommandBuffer.

3

An “available device extension” is a device extension supported by any physical device enumerated by instance.

Valid Usage (Implicit)
  • If instance is not NULL, instance must be a valid VkInstance handle

  • pName must be a null-terminated UTF-8 string

See Also

Document Notes

For more information, see the Vulkan Specification

This page is extracted from the Vulkan Specification. Fixes and changes should be made to the Specification, not directly.

Copyright (c) 2014-2019 Khronos Group. This work is licensed under a Creative Commons Attribution 4.0 International License.